Sweet spot gravel tire width?
 

What's your preferred sweet spot tire width for a 20-25 lb. range gravel bike? I realize terrain matters but at a certain point you might as well be riding a heavier mountain bike or a lighter road bike. I just put a set of 35mm gravel tires on an older steel road bike and I am trying to talk myself out of "needing" another "gravel bike" for the gap between it and my MTB. I only have about 12 bikes I regularly ride. For some reason I can't stop excessively checking Marketplace. LOL

My first gravel bike was limited to 38mm tires, and I ran it with 35s. They served my needs okay for my local riding, as well as a couple of events/races. However, I started feeling the need for a bit more squish, which meant replacing my frame. My new frame will take 50s, and I'm currently running 40s. My normal riding is pavement, dirt fire roads, and mild-to-moderate singletrack, plus some occasional sections of significant chunk. A lot of it is stuff I also ride on my MTB. I'm very happy with the 40mm Tufo Thunder/Swampero combination I'm currently running, and will be using them for my next race in a couple of weeks. That said, there's a growing trend to go wider for gravel, and because I like to experiment and expand my knowledge base, I have a pair of Thundero 48s on the way to me. All that said, it mostly depends on how and where you ride, and what you want from your tires. Among the racing crowd, 40-45 seems to be the most common. Your needs might be different.

I have a fair amount of time on 35mm tires … primarily smooth stuff …

but prefer > 35 mm … so 38 - 42 mm or so …

Currently on 47's and really enjoying the extra width and cushion. The majority of my unpaved riding tends to be flowy, non-technical single track... stuff that would be way overkill for a MTB, but is so much fun on a fat tired drop bar bike.

40mm-45mm.

43mm actual measured width.

Allow me to convert to inches because the math makes more sense. If your mountain bike is 2.25" and your road bike is 1.25", then a logical middle ground for an in-between bike would be 1.75".

Unsurprisingly, this falls in the 40-45mm range. 😉

My gravel bike is currently running 42mm S-works Pathfinder Pros. I was aiming for a fast rolling set up with these and it does that well...these are a really great set up for light gravel or a gravel/road mix. In the future, I might set up another wheel set with 2.0" XC MTB tires...more specifically, the Continental Race Kings(if they'll actually fit.) Not to get too nerdy but, these tires test faster than most gravel tires on the rolling resistance website...I run the 2.2" version on my XC bike and can confirm that they are fast, but with better traction.

I was really hoping that 2.1 Thunder Burts would fit in my frame. They roll surprisingly well (BRR data backs it up). Thicc tire pimp, Dylan Johnson, ran 2.2 Race Kings at the recent Midsouth race. Adam Roberge ran Pirelli H 50s at BWR Utah. Other pro gravel racers I follow are moving incrementally wider. This is the stuff that has me interested to try Thundero 48s on my bike. BRR data indicates only a small penalty in Crr over the Thundero 40s, and the extra cushion is likely to be faster over rough terrain.

I've been running the 2.2 Race Kings on my XC bike this entire season, it was cool to see Dylan Johnson's success at Midsouth on them. They definitely roll faster than they look like they should. My gravel bike officially has room for 50mm tires, 2"=50.8mm, so may come down to how they measure out on a gravel-width rim. I could see the benefit of running the max width possible. My 42mm Pathfinder pros felt fast on the pave and gravel road sections of a recent gravel race, but I seriously felt slow once we got to cobbled-out dirt/rock farm roads. I was just getting bounced around and couldn't pedal consistently enough to hold my "tempo" power.

Not really gravel related, but I'd like to see Conti offer them in a 2.4 width. My XC bike(Santa Cruz Blur 4) came with 2.4 tires and I prefer the trend of wider tires even for XC. I've been on kind of a "nerd" approach to XC in this past year or so...running a bike with more travel than in seasons past(now 120mm FS,) "fast" tires, and I'm even chain waxing now. I'm still a gravel newbie, so I'm trying to keep an open mind, and not just do whatever the "normal" is.

I have a blend of 50% paved road, 25%rail trail (generally nicely packed "champagne" fine gravel or dirt), and 25% dirt roads.

After experimenting a bit I settled on 38mm Rene Herse Barlow pass, which on my 25mm rims and 42psi measures 40mm actual. I am 220lbs combined bike and rider weight (i believe one's personal optimal tire size for a given bike and condition depends on weight).

Very tiny speed tradeoff on pavement (mostly wind and weight not rolling resistance) with this rig, and MUCH faster than 32-35mm on the rail trails, and feels reaonably capable when the trail turns a little bit to sh-t.

38mm (with tubes) on a graveled cx bike is working for me at 170lbs. and 40-ish psi.

[Old man mounting soap box] Before "gravel" bikes were a thing, we all rode cyclocross bikes with 32 or 35mm tires and nobody complained. [Dismounts soap box]

I generally run 40mm tires, some of which will actually measure at 43 or 44mm. I still have a set of 35mm Kenda Alluvium Pros that I really like for mixed surface rides, but that can still handle the nasty stuff. Frankly, if I can't ride something on a 40mm tire, then I want a mountain bike - not so much for the tire width, but more for the flat bar and the frame geometry. I'm in Connecticut, and my riding can range from smooth, maintained dirt roads, to single track trails, to washed out stream beds.

But right now, I would say 40 is my sweet spot.

I've tried a few different gravel tires and don't find that much difference between 35mm and 40mm, and don't think I need anything larger than 40mm for the terrain I ride, so I'd say that size is my "sweet spot".

I agree with all the sentiment here than 40-45 seems to be where the sweet spot is currently being defined.

I'm also curious about how reality out in the real world compares with the BRR lab tests of rolling resistance on that metal drum. It seems to me that a 2.2" MTB tire with widely spaced knobs could logically show a low RR with not a lot of knob in contact with the drum and no uneven terrain or hard edges in the the equation, but potentially have higher actual rolling resistance than a gravel tire out in the real world. My feeling is that it's a big jump from rolling on a drum in a lab to rolling over mixed terrains that this type of riding includes. Heck, even most road surfaces aren't very comparable rolling on that drum. There's also the aero & weight factor to consider and then it's a pretty wide, murky gray area to deem which tire truly has less rolling resistance in the wild.

To BRR's credit, their drum is not smooth. It's diamond plate. This is an attempt to somewhat mimic real world road conditions.

On a gravel tire discussion on another site, I came across some interesting information relating to surface roughness (impedence) and tire aerodynamics...
https://silca.cc/blogs/silca/part-4b...-and-impedance
https://www.swissside.com/en-us/blog...-gravel-riding

In Colorado, I rode 38’s with no problems ever. I even recorded my fastest time up a paved road on them while approaching a gravel road, even faster than I’d done previously on a road bike. Gravelking SK for the win.

Once I moved to Central Oregon, I’ve found that I want wider tires. The moon dust properties of the volcanic rock here necessitates a wider tire. My next tires will be the widest my frame can fit, probably 43-45 for dry condition.

Tight packed gravel is easy. So are rocks. It’s the loose gravel and sand that tests your tires.

I think it depends on the bike (frame, etc).

On the same gravel roads in my area, I’ve used a carbon bike with 43mm tubeless and it was a bit harsh. Yet on a steel frame/fork with the same tires, with tubes, felt much better.

I'm pretty happy with 43mm Gravelking SK on the gravel around here, which can tend to be a bit rough. It also helps with things that might puncture a tire with a little less tread. I replaced one of my SK tires after it had dozens of punctures. It probably would have kept going. I have ridden 40mm Velocitas on smooth gravel, and it worked out fine. I have a GK SS that works okay, I bought it when there wasn't a lot of selection. Probably would have gotten the SK if it had been available.

For me it is all about comfort vs rolling resistance. I rode
35-622 panaracer sk slick
38-622 panaracer comet
45-622 schwalbe G one Bite
38-622 vitoria tereno mix
50-584 conti cross king
50-584 conti race king
52-584 vitoria mezcal
52-584 vittria barzo

the best for me is 50-584 raceking because @ 20-23psi, it is the tyre with the lowest rolling resistance and is very supple. It is fast on tarmac, faster on gravels and is OK in mud

With the types of gravel I encounter (very loose and sometimes sandy) I would not go below 45. I did a gravel race on 40s two years ago and a few sections were unnerving with 40s.

If a gravel bike doesn't accept 45-50 tires I will not buy it.

Pick the right tire and you lose nothing going from 40 to 45-47. But you do gain traction and a more comfy ride.

I'm running the Tufo Gravel Thundero 700 x 44 (that actually measure 45) and they are fast on the paved sections and easy gravel or groad/gravement sections. They rank very well on the rolling resistance test.

First ride on Tufo Thundero 48s last night, on a loop that mixes a wide range of demands. On pavement, they were slower to accelerate, but rolled fairly well considering their size, but felt a bit like driving an old Cadillac - not very sporty. In the dirt, they shine, especially as the handling demands increase. For my local rides, they will be a lot of fun, but for races, I'm going to stick with my 40mm Thundero/Swampero combination.

When doing Ravel and Gravel I am most comfortable between 38mm to 34mm. If I need anything more then its time to go to a Mountain Bike. I have never ridden a True modern day specific Gravel Bike. Just my old beaters. The new Gravel bikes certainly do look real nice.

And for the new Mountain Bikes I have one word, "Complex".

I was running 42s on smooth hard gravel on a current generation high-end gravel/endurance bike. Was like riding a farm tractor. I swapped the tires out for slick 32s pumped up harder, and noticed a definite improvement in speed and cornering.

Final test was going back to my old steel road bike with 23's pumped up hard, and was impressed on how much faster this setup was. Overall bike weights and fit was about the same, although the wheels and tires on the vintage road setup were much much lighter and more responsive. Obviously not for loose conditions. If you go fast enough, the narrow tires just plane over the little stuff.

If I was riding real gravel, then I'd save myself a whole bunch of fuss and money and pull out my 1991 Rocky Mountain with 26" wheels and 2" tires.